Manufacture and treatment of artificial textile materials



Patented May 27, 1941 MAN UFACTUREAND TREATIHENT 0F ARTI- FIOIAIIJ TEXTILE MATERIALS Frank Brentnall Hill and Thomas don,

Jackson, Sponnear Derby, England, assignors to Celanese Corporation of America, a corporation of Delaware No Drawing. Application February15, 1940, Se-

rlal No. 319,076. In Great Britain February 10, 1939 3 Claims. (CL 8-1131) This invention relates to improvements in the manufacture and treatment of artificial textile materials and particularly to improvements in processes wherein such materials are subjected to shrinking operations.

In the production of artificial textile materials it is frequently found desirable to shrink the materials with a view, for example, to increasing their extensibility, or to produce efiects in woven or other fabrics. Thus, for example, artificial filaments or yarns containing the same, may be immersed in or sprayed with a medium comprising a shrinking agent and a diluent until the desired shrinkage is obtained.

It has now been found that the shrinking power for cellulose derivative materials of shrinking media of which the active agent is a non-associated substance may be substantially increased by adding thereto a small proportion 01' an agent containing the group 1 it According to the invention, therefore, textile materials having a basis of a cellulose derivative are subjected, in the absence of tension sufficient to stretch them, to the action of a medium comprising a shrinking agent which is a non--' associated substance, and a small an agent containing the group ll 0 By stating that the shrinking agent is a nonproportion of associated substance is meant that the molecules of the agent have no substantial tendency to associate with other molecules, whether of that substance or of any other substance, and this characteristic is referred "to in the appended claims by the words the molecules of which have no substantial tendency to associate with other molecules."

Very suitable shrinking media, particularly for artificial filaments, yarns or fibres having a basis of acetone-soluble cellulose acetate, comprise such non-associated substances as, for example, methylene chloride and other halogenated hydrocarbons having the characteristics of latent solvents as described in U. S. Patent No. 2,058,422,

diluted with an aliphatic or aromatic hydrocarbon, e. g. benzine, petrol ether, kerosene, benzene, toluene or xylene, or with carbontetrachloride. with such media, the added agents are especially efiective.

Among agents which may with advantage be added to the shrinking media, aliphatic acids are of particular importance for use according to the present invention, particularly in connection with acetone-soluble cellulose acetate. For example acetic acid and formic acid and their homologues, glycolic acid, lactic acid, succinic acid, tartaric acid, citric acid and other hydroxy and/or polybasic carboxylic acids are applicable. However, there may be employed other carboxylic acids, e. g. ben'zoic acid and salicylic acid, and esters, particularly esters having swelling power for the cellulose derivative material to be treated, such as, for example, esters of glycols, e. g. glycol mono-' and di-acetates and the ethyl ether of glycol mono-acetate, dibutyl tartrate, and the alkyl and ketonyl phthalates.

As indicated above, the added agents are employed in small proportions in the shrinking media. Preferably a proportion less than'1% is employed, e. g. 02-05%. For example, materials having a basis of acetone-soluble cellulose acetate may be shrunk in a medium comprising 62-68% methylene chloride and 38-32% kerosene or benzene to which has been added 2-4 ccs. per litre of acetic acid or 0.2-1 gm. per litre of citric acid. In general, no advantage is secured by employing higher proportions of the added agents.

The shrinking media according to the invention may be employed in any of the methods described, for example, in U. S. Patents Nos. 2,070,583 and 2,058,422. The invention is of the greatest importance when applied to the treatment of filaments, fibres, threads, yarns, fabrics and the like containing or derived from high tenacity wet spun filaments or filaments which have been stretched to 200% or more of their original length in hot water or wet steam or in a medium containing an organic solvent or swelling agent. It has been found that when the shrinking media are applied to cut staple fibres,

particularly staple fibres of high tenacity having a basis of a cellulose derivative, a condition in which they are to contract, as described in U. S. application S. No. 306,904 filed November 30, 1939, such fibres acquire a crinkle or crimped efiect which greatly enhances their spinning qualities;

Reference has been made above to materials having a basis of acetone-soluble cellulose acetate, and the invention is of the greatest importance in connection with the treatment of such materials. However, materi lsrmi de from other cellulose acetates or other esters such as, for example, cellulose formate, propionate, and

while they are in butyrate, and mixed esters, e. g. cellulose acetopropionate and aceto-butyrate, and also from cellulose ethers, e. g. methyl, ethyl and benzyl cellulose or from cellulose ether eaters.

The following examples illustrate the invention:--

Example I Dry-spun cellulose acetate yarn, which has been stretched in wet steam to 1000% of its original length, is immersed for minutes at 25 C. in hank form in a bath of 65% methylene chloride and 35% kerosene (percentage by volume) to which 2.5 cos/litre of glacial acetic acid has been added, and allowed to shrink freely. After washing with low-boiling petroleum ether and drying in a current of warm air, the yarn is found to be well shrunk and to have a substantially improved extensibility as compared with that of a yarn which has been similarly treated in a bath free from acetic acid.

Example II Dry-spun cellulose acetate yarn, which has been stretched in wet steam to 800% of its original length, is immersed for 10 minutes at 25 C. in hank form in a bath of 65% methylene chloride and 35% kerosene (percentage by volume) to which 1 gm./litre of citric acid has been added, and allowed to shrink freely. After washing and drying as in Example I, the product is well shrunk and has a substantially greater extensibility than that of yarn similarly treated in the absence of citric acid.

The term "latent solvent as employed in the present specification and claims means an agent which at least at ordinary temperatures is incapable of dissolving the cellulose derivative, but which is capable of swelling the cellulose derivative in a high degree and which becomes a solvent for the cellulose derivative when mixed with a comparatively small proportion of another liquid, particularly an alcohol.

Having described our invention, what we desire to secure by Letters Patent is:

1. Process for improving the properties of textile materials having a basis of an organic derivative of cellulose, which comprises subjecting the materials, in the absence of tension sufficient to stretch them, to the action ofa medium comprising a halogenated hydrocarbon as a latent solvent, and an aliphatic polybasic carboxylic acid in a proportion less than 1% of the medium.

2. Process for improving the properties of cut staple fibers having a basis of an organic derivative of cellulose, which comprises subjecting the fibers, while in a condition in which they are substantially free to contract, to the action 0! a medium comprising a halogenated hydrocarbon as a latent solvent, and an aliphatic polybasic carboxylic acid in a proportion less than 1% of the medium.

3. Process for improving the properties of textile materials having a basis 01 acetone-soluble cellulose acetate, which comprises subjecting the materials, in the absence of tension sufilcient to stretch them, to the action of a medium comprising 62 to 68% methylene chloride and 38 to 32% of a hydrocarbon to which has been added 0.2 to 1 gm. of citric acid per litre of the medium.

FRANK BRENTNALL HILL. THOMAS JACKSON. 

